Lubricating oil composition



United States Patent LUBRICATING on. COMPOSITION Louis A. Mikeska,Westileld, and Charles A. Cohen, Roselle Park, N. J., assignors to EssoResearch and Engineering Company, a corporation of Delaware No Drawing.Original application January 15, 1951, Se-

rial No. 206,313. Divided and this application January 2, 1952, SerialNo. 264,678

3 Claims. (Cl. 252-33) This invention relates to an improved process forpreparing oil-soluble sulfonic acids and their derivatives which areespecially adapted for use as lubricating oil additives.

This invention provides a method for producing oilsoluble sulfonatesfrom specific petroleum white oil fractions. The method compriseschlorinating the White oil, dehydrochlorinating the chlorinated oil andsulfonating the resulting olefins with a sulfonation agent complex.

The white oil utilized is mainly a naphthenic, aromatic free oil (USPpetrolatum liquidum heavy) prepared by the well-known exhaustivesulfuric acid treatment of a heavy petroleum distillate to removesubstantially all aromatics. The properties of the specific oil utilizedhave been found to be quite critical in the process of this invention.Physical inspections should lie within the following limits:

Molecular weight 45060O Specific gravity 60/60 F 0.80-0.90 Sayboltviscosity at 100 F 225-500 Unsulfonated residue 100% Pour point lessthan 30 F.

Petroleum fractions outside the range of this oil do not yieldsatisfactory results, e. g., they either fail to supply appreciablesulfonated products, supply products which are not oil-soluble, or, ifsoluble, then of low potency as detergents.

In accordance with the process of this invention the specific oilfraction is subjected to a chlorinating operation by passing gaseouschlorine into the liquid mixture while maintaining the temperature ofthe mixture substantially low, preferably below 100 C. The passage ofchlorine into the hydrocarbon mixture is continued until the gain inWeight of the hydrocarbon material indicates that the chlorinationreaction has proceeded to the extent desired. A ratio of 0.5 mol (oneatomic weight) of chlorine per mol of hydrocarbon has been found toeffect a satisfactory chlorination of the hydrocarbon. Chlorination inexcess of the indicated level results, on subsequent dehydrochlorinationand sulfonation, in the obtaining of insoluble and, hence, undesirablepolysulfonates, or excessive formation of dienes which have to beeliminated.

When the increase in weight of the white oil indicates that chlorinationhas proceeded to the desired level, the entire body of the chlorinatedmaterial is subjected to dehydrochlorination. This dehydrochlorinationis conducted in liquid phase by conventional means, e. g., thermally, byaqueous alkali, by alcholic KOH, by alkali in glycols, or catalyticallythrough the use of catalysts, such as barium chloride or amines, such asquinoline and collidine, etc., depending upon manipulative advantages.When the dehydrochlorination is done by thermal means alone, the uppertemperature limit is 320 C. The other means of dehydrochlorinationutilize an upper temperature level of 300 C. and usually result in lessundesirable color formation. The gaseous HCl is thus driven oii iceleaving a liquid, predominantly mono-olefinic, product. If excess dienesare present as indicated by the bromine number or the appearance ofdisulfonates in the final product, these dienes can be removed byreaction with maleic anhydride prior to sulfonation. The olefinicmaterial so produced is referred to as white oil olefin in the appendedclaims.

The olefinic product is then sulfonated, preferably on an equimolarbasis. Since these olefins are not sulfonatable by the use of singlesulfonation agents, such as sulfuric acid or sulfur trioxide alone, theymust be sulfonated by a sulfonation agent complex, e. g., sulfuric acidand acetic anhydride, S03 with ethers such as diethyl ether, or dioxane,bromor chlorosulfonic acids and ethers or dioxane, S03 and pyridine andthe like, or mixtures of the preceding. It is to be understood that theterm, sulfonation agent complex connotes complex materials of the natureindicated. A temperature in the range of 20 to C. is maintained duringsulfonation. Inert diluents such as chloroform, petroleum naphtha,sulfur dioxide and acetonitrile may be employed. The oil-solublesulfonic acids which are predominantly in the organic layer aresubsequently neutralized usually with caustic soda or soda ash. Thesodium soaps are then extracted with aqueous-alcoholic solutions such as50% aqueous isopropyl alcohol, 50% aqueous ethyl alcohol, etc. Theneutralization can also be accomplished with caustic soda in 50%isopropyl alcohol. Unchanged hydrocarbons are removed by extraction withnaphtha. The alcoholic solution of the sodium sulfonates is purified,that is, rendered salt-free by dehydration or extraction with sodiumsulfate, sodium carbonate, etc, and the solvent removed leaving a saltand oil-free sulfonate. These sodium salts are then converted in oils bya double decomposition reaction to the corresponding alkaline earthsalts when it is desired to use the latter in lubricating oils. Theacids may also be neutralized directly with calcium hydroxide, bariumhydroxide, nitrogen bases, etc.

The following examples are given to illustrate this invention andinclude both the processing of the white oils according to thisinvention and test results on the products as oil-soluble detergents.

EXAMPLE I Chlorination of white oils Distillate Finishggl] WhiteSpecific Gravity, 60/60, F 0 8990 Flash, F Viscosity, S. S. U., at F 538Viscosity, S. S. U., at 210 F Viscosity Index. A. S. T. M. Pour, ColorAniline Point, F Unsulfonated Residue The above-described oil waschlorinated as follows:

A three-necked flask equipped with a stirrer, a return condenser and athermometer was charged with 1227 grams of the oil, the temperature wasraised to 70 C. whereupon chlorine was bubbled through the mixture at arapid rate. Throughout the reaction the temperature was maintained at70-80 C. When the reaction mixture had ether.

gained 120 grams, the reaction was discontinued and nitrogen was blownthrough the mixture in order to re were removed and that the ultimategain in weight .amounted to 115 grams.

Without any further purification the product was submitted for analysisand was shown to contain 8.97% chlorine.

EXAMPLE Ir 7 Dehydrohalogenation of the chlorinated oil The chlorinatedoil described 'above was dehydrohalogenated as follows:

. Four hundred grams of the chlorinated oil were placed into athree-wayflask fitted with a stirrer, athermometer and a return condenser. Themixture was then heated, with-stirring, to 160 C. at which point. arapid evolution of hydrogen chloride took' place. When thereactionsubsided, the temperature was raisedto 190 C. and again maintained atthislevel until the evolutioned gas hadsubsided. Finally, thetemperature was raised to 310 C. and maintained at this point forminutes.

' Qualitative tests had now shown that the reaction product was free oforganic chlorine. Passage of nitrogen through the mixture which had beenmaintained throughout the reaction, was continued for another half-hourto a The dehydroremove. last traces of hydrogen chloride.

halogenated material consisted of 342 grams of dark viscous oil whichwas distilled from a Claisen flask under Sulfonation of the unsaturatedoil 'A three-way flask equipped with a stirrer, a return condenser, anda dropping funnel was charged with 228 gms.

of the dehydrohalogenated oil (fraction H) and 300 ml.

hexane. The dropping funnel was charged with 115 gms. of chlorsulfonicacid dissolved in 180 ml. of dry ethyl The acid-ether complex was thenadded slowly to the reactor at room temperature. No rise in temperaturewas noted during the addition of the complex. When this operation wascompleted, the temperature was raised to 40 C(and maintained at thislevel for about 2 hours.

Finally, the product was transferred into a separatory funnel anddiluted with 450 ml. of hexane and time was sodium carbonate. 7 Onstanding, two layers were obtained. The upper layer consisted of hexaneand unreacted white oil. The lower, alcohol-water layer con-' tained thedesired soapQ The lower layer was extracted twice more with hexane toremove thelast traces of oil.

Thewater-alcohol layer was now saturated with sodium carbonate at 50 C.Two layers were again obtained. The lower-layer, which consisted of awater solution of inorganic salts, was discarded. The upper layer, whichconsisted of an alcoholic solution of the desired sulfonates, was driedon a drum'drier. The dry soap'thus obtained consisted of grams of lightcolored solid which proved to be readily soluble in ethyl ether, and innaphthenic as well as in paraffinic lubricating oils. The sulfonate hada combining weight of 537, which indicates a certain amount of polymericmaterial.

4 EXAMPLE IV Calcium salt of white oil-olefin sulf 320 grams of 30 wt.per. cent solution :of thesodium salt of the sulfonatepreviouslydescribed, in an extracted Coastal distillate having a Sayboltviscosity at F. of

seconds, were charged to a 2-liter beaker and heated to 95 C. To the oilwas then added 150 grams of a preheated 20 wt. per cent solution ofcalcium chloride in water. The mixture was then brought tothe boilingpoint with stirring and heating continued at the boiling point for 15minutes. Stirring was then stopped and the beaker contents allowed tosettle in a steam bath held at 9698 C. The lower brine layer whichseparated out was siphoned 0E, 15 grams of hydrated lime, Ca(OI- 1)zadded, and heating and stirring continued until the temperature reachedC. At this temperature, 5 grams of a diatoma'ceous filter-aid was added,the temperatureraised to C., and the mixture filtered thru a precoatedfunnel with the aid of vacuum. A clear. fluid productwas obtained havingthe following inspections:

Sulfated ash=5.88 weight per cent Calcium=l.98 weight per centSulfur=2.20 weight per cent Alkaline neut. No.=13.6 mg.'KOH/ gm.

EXAMPLE V Behavior of product in engine tests Lauson Engine Tests weremade on a series of lubricating oils. The-first, the control, was alubricating oil containing some additives but no detergent additive. Thesecond test was made with an oil of the same composition to which hadbeen added 3 weight per cent of a calcium sulfonate prepared accordingto this invention. The results of these tests are tabulated'below and itisclear from these data that the product of this invention is a superiordetergent additive for lubricating oils.

Lauson Engine Test Varnish Detergent Additive Demerlt' Rating OilI-None.-. 4. O0 Oil I+White oil olefin-Ga sulfonate 1 3. 00

3 weight percent. 7

These results clearly indicate how the sulfonates pro-' duced by thisinvention minimize undesirable varnish .de-

posits. a g V The sulfonic acids and sulfonates formed from the whiteoils by the method described are indicated to be largely. non-aromaticcompounds containing naphthenic rings, such as 5 carbon rings. Thesulfonation forms true sulfonic acids and not acid sulfates from the.dehydrochlorinated naphthenes because the .sulfonic. acids are stableagainst hydrolysis. sulfonates are also indicated to contain one doublebond linkage to the carbon constituent that is joined to the 'sulfonicacid or sulfonate group. The uniformity of products obtained through thesteps taken is surprising, taking into consideration the complex natureof white oils and variations of its chlorinated derivatives. Thesulfonates. obtained are soluble in high-boiling petroleum oils and arewater immiscible.

Theproducts from the process of-this invention'are thus true sulfonates,i. e., have a C to S linkage and do not undergo hydrolysis aftertreatment with HCl for four hours. They are thus valuable textile andlubricating oil additives when added in an amount between about 0.1% upto as much as 10% by weight of. the oil. The resulting compositionsexhibit improved lubricating .properties especially in heavy dutyservice such as encountered in diesel engines, aircraft .engines,,andthe like.. Oils containing the compounds of this invention have a de-The sulfonic acids and a tergent action on the parts of the engine thatthey lubricate and are capable of being used under increased loads andtemperatures without causing seizure of bearings or stick ing of pistonrings by formation of varnish. Oils compounded with these sulfonatesalso act as rust preventatives in the engine during period ofquiescence.

It is to be understood that the invention is not limited to the specificexamples which have been offered merely as illustrations sincemodifications may be made without departing from the spirit of theinvention.

This application is a division of Serial Number 206,313, filed January16, 1951.

What is claimed is:

1. An improved lubricating composition which com prises a majorproportion of a mineral lubricating oil and a minor proportion,snflicient to improve the de tergency characteristics of saidlubricating oil of a naphthenic non-aromatic calcium sulfonate of awhite oil olefin, said white oil olefin having a molecular weight in therange of 450 to 600 and being derived from a naphthenic, non-aromaticwhite oil by chlorination with not more than about 0.5 mol of chlorineper mol of hydrocarbon at an elevated temperature below 100 C., followedby dehydrochlorination.

2. An improved lubricating composition which comprises a majorproportion of a mineral lubricating oil and 0.1 to 10% by weight basedon the weight of lubricating oil of a naphthenic non-aromatic calciumsulfonate of a white oil olefin, said white oil olefin having amolecular weight in the range of 450 to 600 and being derived from anaphthenic, non-aromatic white oil by chlorination with not more thanabout 0.5 mol of chlorine per mol of hydrocarbon at an elevatedtemperature below 100 C., followed by dehydrochlorination.

3. An improved lubricating composition which comprises a majorproportion of a mineral lubricating oil and about 3% by weight based onthe weight of lubricating oil of a naphthenic non-aromatic calciumsulfonate of a white oil olefin, said white oil olefin having amolecular weight in the range of 450 to 600 and being derived from anaphthenic, non-aromatic white oil by chlorination with not more thanabout 0.5 mol of chlorine per mol of hydrocarbon at an elevatedtemperature below 100 C., followed by dehydrochlorination.

References Cited in the file of this patent UNITED STATES PATENTS

1. AN IMPROVED LUBRICATING COMPOSITION WHICH COMPRISES A MAJORPROPORTION OF A MATERIAL LUBRICATING OIL AND A MINOR PROPORTION,SUFFICIENT TO IMPROVE THE DETERGENCY CHARACTERISTICS OF SAID LUBRICATINGOIL OF A NAPHTHENIC NON-AROMATIC CALCIUM SULFONATE OF A WHITE OILOLEFINE, SAID WHITE OIL OLEFIN HAVING A MOLECULAR WEIGHT IN THE RANGE OF450 TO 600 AND BEING DERIVED FROM A NAPHTHENIC, NON-AROMATIC WHITE OILBY CHLORINATION WITH NOT MORE THAN ABOUT 0.5 MOL CHLORINE PER MOL OFHYDROCARBON AT AN ELEVATED TEMPERATURE BELOW 100* C., FOLLOWED BYDEHYDROCHLORINATION.